The present invention relates to medical imaging of the heart, and more particularly, to measuring a volume of the left ventricle of the heart in 3D cardiac CT volumes.
The volume of a heart chamber and its dynamic change over the course of the heart cycle are important parameters in evaluating the functionality of the heart. The dynamic change of the volume of a heart chamber over the course of the heart cycle is typically measured as the ejection fraction (EF) of the heart chamber. Generally, the volume of a chamber at a given time can be determined by measuring the volume of the blood pool contained in the chamber. Typically, the volume of the left ventricle (LV) of the heart is determined in 3D CT volumes either by deformable model based automatic or semi-automatic methods or by thresholding based on voxel intensity using a contrast agent. Due to the complex geometric relationship of the papillary muscles and the blood pool in the LV, deformable model based automatic or semi-automatic methods typically include the papillary muscles in the volume measurement of the LV. In conventional thresholding techniques, if the contrast agent is used appropriately, the blood pool is typically brighter than the papillary muscles, which have similar intensity to the myocardium. Using a carefully tuned threshold, which typically must be tuned manually, the blood pool is separated from the papillary muscles and myocardium. Therefore, conventional thresholding techniques typically exclude the papillary muscles from the volume measurement of the LV.
Since deformable modeling and thresholding approaches are both commonly used in practice, two different LV volume measurements (including and excluding papillary muscles) are commonly used. Cardiologists have not achieved agreement regarding which volume measurement should be used. Accordingly, it is desirable for a method to accurately, efficiently, and automatically measure the LV volume both including the papillary muscles and excluding the papillary muscles.